Apparatus for producing precured retreaded tire

ABSTRACT

The present invention relates to a method of producing a precured retreaded tire, etc., and the purpose of the invention is to produce the tire with saving space and power. Here, a precured retreated tire means a tire made by linking a plate rubber member, which has been vulcanized and molded so as to form tire grooves in advance, to a circumferential surface of a buffed abraded tire without vulcanizing said plate rubber member. A producing method according to the present invention comprises a step to insert a bladder (30) into a tire (T), a step to closely connect a plate of once vulcanized rubber member (T1) to a circumferential face of a buffed tire with an unvulcanized linking rubber (R) placed therebetween by attaching an envelope (48) to an outer circumferential face of the tire with fluid pressure, and a step to vulcanize the linking rubber by a heating device (46) and integrally combine the plate rubber member to the circumferential face of the tire, in order.

FIELD OF THE INVENTION

The present invention relates to a method of producing a precuredretreaded tire and an apparatus therefor. Here, a precured retreadedtire means a tire made by binding a plate rubber member, which has beenvulcanized and molded so as to form tire grooves in advance, to acircumferential surface of a buffed abraded tire without vulcanizingsaid plate rubber member.

BACKGROUND OF THE INVENTION

In a conventional method of producing a precured retreaded tire, firstas shown in FIG. 11, a belt plate of rubber member T1, which has beenvulcanized and molded so as to form tire grooves "d" in advance, isclosely rolled onto a circumferential surface of a buffed abraded tire Twith a thin plate of unvulcanized rubber R whose width is approximately1 mm placed therebetween for linkage. Next, as shown in FIG. 12, aninternal pressure tube 1 is put inside the tire T, a sectionallyU-shaped ring envelope 2 made of thin rubber is bound to cover thecircumferential and side faces of the tire T, and divided rimsconsisting of a female rim 3 and a male rim 3' are imposed thereon. Saidfemale rim 3 consists of a support tube 3a and a ring plate 3b, and saidmale rim 3' consists of an insert tube 3c and a ring plate 3d. Afterpreparing plural numbers of tire sets T' in the above condition, asshown in FIG. 13, those tire sets T' are hung onto a supporting beam 4aof a hanging stand 4 with the tire sets T' closely connected with eachother by means of suitable clamps. Next, the hanging stand 4 is putinside a pressure type heating tank 5. At the same time, by supplyingair of about 8 kg/cm² to said internal pressure tube through a supplyport 1a. . . as well as sucking air from an exhaust port 2a . . . ofsaid envelope 2, a vacuum is produced therein so that the plate rubbermember T1 is closely attached to the circumferential surface of the tireT. After closing a cover 5a of the heating tank 5, steam at about 100°C. is supplied therein and circulated by a fan, etc. Here, the internalpressure is about 6 kg/cm². This state is kept for about four hours, andthrough this a thin plate of linking rubber R is thouroughly vulcanized.Accordingly, the plate of previously vulcanized rubber T1 is integrallycombined with the circumferential surface of the tire T so as to finisha retreaded tire.

In the above-mentioned conventional producing method, because a hugeheating tank and a boiler for producing steam for said tank, etc., areused, a wide space is necessary for installing them. Besides, there issuch a disadvantage that a rubber member is damaged and abraded becauseof its direct contact with steam. Furthermore, operations such asinserting the internal pressure tube into the tire T, covering the outersurface of the tire T with the envelope 2, installing both the rimmembers 3 and 3' to the tire T, inserting the tire sets T' in theheating tank 5, etc. are actually manually conducted, and thereforerationalization of the operations is required. The object of the presentinvention is to solve these problems.

SUMMARY OF THE INVENTION

The present invention comprises a step to insert a bladder (an internalpressure tube) into a tire, a step to closely connect a plate of apreviously vulcanized rubber to a circumferential face of a buffed tirewith an unvulcanized linking rubber placed therebetween by attaching anenvelope made of elastic and deformable rubber sleeve to the outercircumferential face of the tire with fluid pressure, and a step tovulcanize the linking rubber by a heating device and integrally combinethe plate rubber member to the circumferential face of the tire. In thiscase, it is preferable to use a far infrared heating device as a heatingdevice.

In this invention, a boiler is not necessary because precured retreadedtires are mechanically continuously produced. Besides, it settles aconventional problem that an envelope, etc. is worn because of directcontact with steam.

A device for the above-mentioned invention is characterized by that atire loader device for continuously providing a tire, a lower ringdevice for placing a tire thereon by said tire loader device, and alower rack having form members which contact with a lower side of thetire are provided, that an upper rack having an upper ring device forpushing the tire placed on said lower ring device, form members whichcontact with an upper side of the tire, and a heating furnace device forcovering the outside of the tire is provided to the movable in upwardand downward directions, that said heating furnace device comprises ajacket for covering a circumference of the tire, a far infrared heatingdevice provided along an inner circumferential face of the jacket, andan envelope made of an elastic and defomable rubber sleeve providedinside the heating device, that a bladder of the lower ring device isinserted into the tire by a related operation of the lower and upperring devices, that the envelope is attached to a required position on anouter surface of the tire with fluid such as air, and that a linkingrubber for the tire is vulcanized by the far infrared heating device.According to this device, it is possible to further compact a wholedevice besides to provide the above-mentioned advantages.

The envelope of the above heating furnace device is put in a cylindricalcage fitted inside the jacket, and both ends thereof are folded to theoutside at each edge of the cage. The envelope can be pressed and sealedto liner rings and/or the jacket for preventing the cage from gettingout so as to be fixed there. The fixed envelope can be suitablyelastically deformed by fluid pressure (such as air) supplied to a spacebetween the envelope and the jacket, and it can be changed and installedeasily.

According to the above invention, operations such as manually installingan inner pressure tube or an envelope, inserting conventional tire setsinto a heating tank, etc. are not necessary at all. Since precuredretreated tires can be mechanically and automatically produced, manualoperations are greatly reduced, thereby reducing personal expenses andlabor in a great measure. Besides, because a big heating tank, etc. isnot necessary, an installing space for the device becomes relativelysmall.

Especially if a far infrared heater is used as a heating device, aboiler also becomes unnecessary, and therefore the device can be furthercompacted.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a device according to the present invention.

FIG. 2 is a plan view of said device.

FIG. 3 is a side elevational view of said device.

FIG. 4 is a side elevational explanatory view of said device.

FIG. 5 is a side elevational sectional view to show a pre-operatingcondition of a lower ring device of said device.

FIG. 6 is a side elevational sectional view to show a under-operatingcondition of said lower ring device.

FIG. 7 is a side elevational sectional view to show a under-operatingcondition of said lower ring device.

FIGS. 8(a)-8(f) is an explanatory view to show a forming step of aheating device according to the present invention.

FIG. 9 is a partial sectional view to show a under-operating conditionof said device.

FIG. 10 is a partial sectional view to show a under-operating conditionof the heating device of said device.

FIG. 11 is a sectional view of a tire to be processed.

FIG. 12 is a sectional view of a conventional set of tire.

FIG. 13 shows a conventional example.

PREFERRED EMBODIMENTS OF THE PRESENT INVENTION

An embodiment of the present invention is now explained in FIGS. 1-10.First, a device for the present invention is explained.

In the accompanying drawings, reference number 6 shows a lower rackwhose both sides are supported by a pair of side frames 7,7, andreference number 8 shows an upwardly and downwardly movable upper racksupported by means of upwardly and downwardly movable guide shafts 9, 9supported by guide bearings 7a, 7a fixed to side frames 7, 7respectively. A rack closing device 10A for driving the upper rack 8 inupward and downward directions comprises hydraulic closing cylinders 10,10 supported by the side frames 7, 7 respectively, and piston rods 10a,10a whose tip ends are combined with the upper rack 8 by means ofbracket members 11 and Y-shaped members 12.

Reference number 13 shows a tire loader device connected to the lowerrack 6, and reference number 14 shows a lower ring device provided onthe lower rack 6. In this case, the tire loader device 13 comprisesloader cylinders 15 . . . supported by the side frames 7, 7respectively, arms 16 . . combined and worked with piston rods of saidloader cylinders 15, shafts 17 . . whose one end is fixed to said arm16, a ]-shaped bearer arm 19 fixed between the side frames to turnablyhold the shaft 17, a tire bearer 20 fixed to the arm 19, and a stopmember 21 fixed to the bearer 20. The tire bearer 20 is rocked anddisplaced from a position shown in FIG. 3 to a position shown byimaginary lines in FIG. 4 by stretching motions of the loader cylinder15. The lower ring device 11 comprises a lower ring cylinder 24 fixed toa cylinder mounting eye 22 by means of supporting members 23 saidcylinder mounting eye 22 being connected with the lower rack 6, acylindrical lower ring mounting bracket 26 fixed by means of a flange ofa lower push rod 25 screwed to a tip end of a piston rod of the lowerring cylinder 24, a lower bead ring 27 fixed to a tip edge of the lowerring mounting bracket 26, a bladder mounting clamp ring 28 providedinside the bracket 26 to be upwardly and downwardly displaceable acylindrical guide ring 29 fixed to the ring 28, a bladder (an innerpressure tube) 30 provided between circumferential walls of the ring 29and the bracket 26 and fixed to the clamp ring 28, suitable numbers(two, for example) of guide rods 31, 31 vertically provided on a lowerface of the clamp ring 28 by passing through a bottom plate of thebracket 26, a pair of bladder lock cylinders 32, 32 fixed to facingsides of the cylinder mounting eyes 22, bladder rock pins 33, 33provided in holes 22a, 22a formed in thick parts of the mounting eyes 22and fixed to tip ends of piston rods of the cylinders 32, 32, and guiderod bearings 34, 34 fixed to a pair of vertical holes 22b, 22b formed inthe mounting eye 22 to intersect with the holes 22a, 22a respectively.The lower ring device 14 is displaced from a position shown in FIG. 5 tothat in FIG. 6 by stretching motions of the lower ring cylinder 24. Whenthe guide rods 31, 31 are locked by stretching motions of the bladderlock cylinders 32, 32, as shown in FIG. 7, and then downward pressingpressure is given to the lower push rod 25, the lower ring mountingbracket 26 is displaced downward without positional changes of the clampring 28, the bladder 30 and the guide ring 29. Furthermore, when thelower ring cylinder 24 shown in FIG. 5 is stretched again to theposition shown in FIG. 6, and then the guide rods 31, 31 are unlocked byretracting motions of the bladder lock cylinders 32, 32, and then thelower ring cylinder 24 is retracted, the clamp ring 28, the bladder 30,the guide ring 29, and the lower ring mounting bracket 26 are displaceddownward together and return to the position shown in FIG. 5.

Reference number 35 is a circular adiabatic board fixed to an uppersurface of the lower rack, and reference number 36 is a form memberfixed thereon, which consists of a side plate 36a and a sub plate 36b.Reference numbers 37, 37 are a pair of rack clamp devices provided inboth sides of the lower rack 6, which consist of ]-shaped clampers 38,38 and press lock cylinders 39, 39 fixed to the side frames 7, 7 to movesaid clampers in right and left directions in FIG. 1.

Reference number 40 is an upper push rod fixed to a lower face of theupper rack 8, and provided right above the above-mentioned lower pushrod 25. The upper push rod 40 forms an upper ring device with a latermentioned upper bead ring. Reference number 41 is a circular adiabaticboard fixed to the lower face of the upper rack, and reference number 42is a form member fixed thereunder, which consists of a side plate 42aand a sub plate 42b. Reference number 43 is an upper bead ring fixed toa lower edge of the form plate.

Reference number 44 is a heating furnace device, which forms a heatingfurnace with the above mentioned form plate. The heating furnace device44 consists of a cylindrical jacket 45 for covering a circumference ofthe tire, a heating device 46 provided along an inner circumferentialface of said jacket 45, and an envelope 48 of a rubber sleeve fixedinside said heating device 46 by means of a cage 47. In this case, ribs45a, 45b are provided on upper and lower parts of the jacket 45 to fitthe cage 47 therein, as shown in FIG. 8(e) and (f). The heating device46 is an electric far infrared heater, wherein loop electric heat tubes46a . . . are provided at many stages, though it is not restricted tothis means. The cage 47, as shown in FIG. 8(a), is formed by connectinga number of bars 47c with two rings 47a, 47b, and rubber liners 47d, 47dmade of hard rubber are fixed to an outer face of each ring 47a, 47b.The envelope 48, as shown in FIG. 8(b), is a simple cylinder made ofelastic and extensible material (including an equal to rubber).Reference number 49, as shown in FIG. 8(c) and (f), is a liner ring forpushing the envelope 48 and prohibiting the cage 47 from getting out.Said liner ring 49 is circular, and provided with projections 49a to beinserted between an outer circumferential face of the ring 47a of thecage 47 and an inner circumferential face of the rib 45b. It is boltedto an upper surface of the rib 45b.

In fixing the above mentioned envelope 48, first the envelope 48 isinserted in the cage 47, as shown in FIG. 8(c). Next, both edges of theenvelope 48 are folded to the outside, as shown in FIG. 8(d). Then, itis inserted in the jacket 45, as shown in FIG. 8(e), and the liner ring49 is bolted thereto, as shown in FIG. 8(f). By this, a lower edge ofthe envelope 48 is pressed by the rib 45a of the jacket 45 to be sealed,while upper edge thereof is pressed by the liner ring 49 to be seated aswell. Accordingly, an annular sealed up space S is formed in the outercircumferential side of the envelope 48. Fluid pressure of compressedair, etc. is ventilated to the sealed up space S through a suitable path45c.

Next, working processes in producing a precured retreated tire by theabove mentioned device are explained.

First process is to insert a bladder 30 in a buffed tire T mechanicallyand give inner pressure therein with fluid pressure. Specifically, atire T shown in FIG. 11 is put on a tire bearing 20, as shown by solidlines in FIG. 4. In this case, a tire T may be manually set orautomatically set by a suitable feeding device. Next, a loader cylinder15 is automatically or manually stretched. By this operation, a tireloader device 13 displaces a tire T with the tire bearing 20 to theposition shown by imaginary lines in FIG. 4. In conjunction with thedisplacement, a lower ring cylinder 24 begins to be stretched, and alower ring device 14 shown in FIG. 5 is displaced to the position shownin FIG. 6. Accordingly, a lower bead ring 27 is fitted to a lower beadof the tire T so as to support the tire T. Then, a lower ring mountingbracket 26 is raised so as to lift the tire T above the tire bearing 20.On the other hand, in conjunction with this, the loader cylinder 15 isnow retracted, and the tire bearing 20 returns to the original positionshown by solid lines in FIG. 4. When the lower ring cylinder 2F israised to the highest position, the bladder lock cylinders 32, 32 arestretched, and the bladder lock pins 33, 33 are displaced to theposition shown by imaginary lines in FIG. 6 so as to prevent guide rods31, 31 from moving downward. Afterward, closing cylinders 10, 10automatically begin to be retracted, and a rack closing device 10Alowers an upper rack 8. Accordingly, an upper bead ring 43 fits to anupper bead of the tire T, and pushes it moderately. On the other hand,as shown in FIG. 7, an upper push rod 40 abuts on a lower push rod 25,and pushes it down, thereby lowering the lower ring mounting bracket 26connected with said lower push rod 25. In the process of lowering thelower ring mounting bracket 26, the tire T is held between the lowerbead ring 27 and the upper bead ring 43, and lowered with these rings 27and 43. On the other hand, as the lower ring mounting bracket 26 islowered, the bladder 30 is gradually exposed and inserted into the tireT along an inclined outer surface of the upper bead ring 43. Duringthis, working fluid in the lower ring cylinder 24 is discharged througha suitable pressure releasing valve by the pushing pressure of the upperpath rod 40. When the lower ring mounting bracket 26 is lowered to theoriginal position shown in FIG. 5, the bladder 30 is completely insertedinto the tire T. On the other hand, in conjunction with this, press lockcylinders 39, 39 are streched, and clampers 38, 38 fit both sides of theupper rack 8 and the lower rack 6, thereby restricting their relativeposition. Then, pressure fluid such as air (about 10 kg/cm² at most) isfed into the bladder 30 from the outside through a suitable path,thereby supplying inner pressure to an inner face of the tire T, asshown in FIG. 10. In this case, an outer side face of the tire T issupported by form plates 36 and 42, and closely connected with surfacesthereof by the inner pressure of the bladder 30.

The next process is to automatically attach an envelope 48 to the outersurface of the tire T by fluid pressure. The specific process is asfollows. When the inner pressure is given to the tire T in the previousprocess as shown in FIG. 10, in conjunction with this, pressure fluidsuch as air (about 8 kg/cm² at most) is now automatically supplied tothe sealed up space S in the outer circumferential side of the envelope48 through a suitable path 45c. In this case, pressure of the pressurefluid is set smaller than that of the bladder 30. By this, the envelope48 is elastically transformed and pressed to the outer surface of thetire T and the surfaces of the form members 36, 42 to cover them.Accordingly, a plate rubber T1 and a linking rubber R are firmly andclosely connected to a buffed face of the tire T. In the process ofexpanding the envelope 48, air left among the envelope 48, the formmembers 36, 42, and the tire T is discharged through releasing holeswhich are suitably provided on the form members 36, 42.

The last process is to vulcanize the linking rubber R by a heatingdevice 46, and to integrally combine the once vulcanized plate rubber T1to the outer surface of the tire T. Specifically, when the envelope 48adheres to the tire T, it is detected by detecting the pressure in thesealed up space S. In conjunction with this detection, electricity issupplied to a far infrared heater of the heating device 46, and farinfrared rays are radiated toward the tire T. By the great penetratingeffects of the far infrared rays, the linking rubber R is uniformly andeffectively heated. In this case, a heating temperature of the heatingdevice 46 is so set that the linking rubber R becomes at about 100° C.The heating is carried out for several hours.

When each of the above-mentioned processes is over, the pressure fluidin the sealed up space S and the bladder 30 is automatically blown. Onthe other hand, the press lock cylinders 39, 39 are retracted so thatthe clampers 38, 38 release the positional restriction of the upper rack8 and the lower rack 6. After the closing cylinders 10, 10 are stretchedso as to raise the upper rack 8 to the original position, the lower ringcylinders 24 is stretched again so as to displace the lower ringmounting bracket 26 to the position shown in FIG. 6. In conjunction withthis, the loader cylinders 15 . . . are stretched, and the empty tirebearing 20 is displaced again to the position shown by imaginary linesin FIG. 4. Then, the bladder lock cylinders 32, 32 are retracted so asto retreated the bladder lock pins 33, 33 to the original position.Then, the lower ring cylinder 24 is retracted so that the lower ringmounting bracket 26 and the bladder mounting clamp ring 28 areintegrally lowered to the original position shown in FIG. 5. During thislowering process, a processed tire T is supported by the waiting tirebearing 20, being placed thereon. The tire bearing 20 supporting thetire T returns to the original position by the loader cylinders 15 . . .which are retracted in conjunction with the retraction of the lower ringcylinder 24, and then the tire T is taken out, as shown in FIG. 4.

In the above-mentioned embodiment, heating of the heating device 46 iscarried out by a far infrared heater from only the outer peripheral faceof the tire T. However, it is also possible to heat the tire from sidefaces thereof, or to heat the tire indirectly by using steam. Thoughthey are not illustrated, suitable reflecting mirrors are providedoutside the far infrared heater to use heat waves effectively. It ispreferable to preliminarily supply a small amount of pressure fluid tothe bladder 30 to expand it slightly and to keep it in a required form,before starting the real supply of the fluid. Besides, in order to dealwith tires of different sizes, some form members 36, 42, upper beadrings 43, and lower bead rings 27 of different sizes are prepared.

I claim:
 1. An apparatus for producing a precured retreaded tire from abuffered tire, a plate of vulcanized rubber juxtaposed with acircumferential face of the buffered tire, and a member of unvulcanizedlinking rubber placed between the belt and the buffed tire comprising:atire loader device for continuously providing a buffed tire; a lowerring device for receiving thereon the buffed tire from said tire loaderdevice; a lower rack having form members which contact a lower side faceof the buffed tire; an upper rack having an upper ring device forpushing the buffed tire placed on said lower ring device and formmembers for contacting an upper side of the buffed tire; and a heatingfurnace device movable in upward and downward directions for coveringthe outside of the buffed tire, said heating furnace device including ajacket for covering a circumference of the buffed tire, a heating deviceon an inner circumferential side of the jacket, and an envelope made ofa deformable rubber sleeve inside the heating device, wherein the lowerring device has a bladder insertable into the buffed tire by a relatedoperation of the lower and upper ring devices, the envelope isengageable with the plate of vulcanized rubber by the use of fluidpressure, and the unvulanized linking rubber for the tire isvulcanizable by the heating device.
 2. An apparatus for producing aprecured retreaded tire according to claim 1, wherein the heating deviceis a far infrared heater positioned along the inner circumferential faceof the jacket.